Only the top layer of the ocean gets a lot of sunlight.
Many marine animals aren't in the dark, however, because they make their own light. Some animals, like the Bermuda fireworm, use a process called bioluminescence (BY-oh-loo-min-ESS-ince). Chemicals in the bodies mix together to produce "cold light," which doesn't give off any heat. Some bioluminescent animals, like the anglerfish, get their glow from tiny microbes that live inside special light organs in their bodies.

The blue-ringed octopus uses fluorescence, another process that can cause things to glow. When disturbed, blue circular rings flash all over its body. Instead of making their own light, they can absorb and re-emit light from outside their bodies.

Sing along with our favorite
animals that glow: the anglerfish,
Bermuda fireworms,
and a blue-ringed octopus!